(a) Field of the Invention
This invention relates to folding portable electronic devices and particularly relates to those in which a display part is supported changeably between a vertical position and a horizontal position.
(b) Description of Related Art
A recent trend has been to watch TV away from home using a folding mobile phone. Folding mobile phones generally have a display part longitudinally extending when the user holds it in his or her hand. Therefore, when the user watches TV on the longitudinally-extending display part, the size of the TV screen is very small with respect to the total display size. There have been conventional conflicting needs, i.e., a portability need to make the folding mobile phone size as small as possible and a visuality need to watch TV on a large screen.
If the mobile phone itself is horizontally oriented and the screen is changed to a landscape mode, TV screen images can be displayed on the full display. To keep the display part of the mobile phone horizontally oriented, it is necessary to keep on holding the mobile phone, as turned 90 degrees into a horizontal position, with one hand or both hands or to stably keep the horizontally oriented folding mobile phone with a special holder. However, it is difficult to continue to watch TV while holding the mobile phone with one hand or both hands and to find an appropriate holder away from home.
To cope with this, some techniques have been proposed in which the display part, which is provided on an upper housing of the folding mobile phone, is turned 90 degrees with respect to a lower housing thereof and the back face of the lower housing is left to rest on a place where the mobile phone is, thereby relatively stably putting the mobile phone on the place while allowing TV watching.
For example, Published Japanese Patent Application No. 2001-156893 discloses a folding portable electronic device in which the display part is supported to a first housing changeably from the vertical to horizontal position with the portable electronic device itself held in the vertical position in hand. Specifically, the folding portable electronic device has a pivot pin provided at the center of the display part and extending orthogonally to the display part, whereby the display part can be turned 90 degrees about the pivot pin.
Published Japanese Patent Application No. 2003-114670 discloses a portable electronic device including: a first casing having a large number of input keys; a second casing having a display part capable of displaying letters and images; a link member hinge-jointed at one end to the first casing foldably together and connected at the other end in contacting relation to one region of the second casing; a pivotally actuating means, disposed between the one region of the second casing and the other end of the link member, for pivotally moving the second casing along the contact surface with the link member within a predetermined range of angles; and a signal processor for converting an image displayed on the display part when the second casing is pivotally moved by the pivotally actuating means. According to the portable electronic device, the display part can change its position from vertical to horizontal or vice versa and can also change its screen size.
Alternatively, a known folding portable electronic device disclosed in Published Japanese Patent Application No. 2003-319043 has a support mechanism that supports a display part slidably and pivotably on a first housing. According to the folding portable electronic device, the display part is first vertically slid and then moved pivotally about a pivot pin provided at the center of the display part. Therefore, the display part can accordingly avoid its contact with the hinge and a swelled part provided at the lower end of the first housing and thereby increase the display size.
Furthermore, another known folding portable electronic device as disclosed in Published Japanese Patent Application No. 2006-211576 includes a first housing including a display part provided at a surface thereof, a second housing including an operating part provided at a surface thereof and a hinge connecting the first and second housings to allow the first and second housings to be freely opened and closed in their folded form, wherein the display part is supported to the first housing through a support mechanism changeably between a vertical position and a horizontal position and the support mechanism is configured to guide and support the display part to allow the display part to change between the vertical and horizontal positions so that a lower corner of the display part moves along the hinge when the display part is changed in position.
In all of the above known techniques, a mechanism for turning the display part is provided on the back face so that the display part can be turned from the vertical to horizontal position in a single direction. Thus, the display part can be oriented vertically and horizontally and the image size to be displayed thereon can be changed.
However, as can be expected, whether the direction to provide ease of turning operation of the display part is clockwise or counterclockwise as viewed from the front depends upon whether the user is right-handed or left-handed. Furthermore, it can be expected that which direction provides ease of turning operation of the display part depends also upon whether the user holds the portable electronic device in the right hand or the left hand.
With the configurations as disclosed in Published Japanese Patent Applications Nos. 2001-156893 and 2003-114670, since the display part is supported to the first housing by a single pivot pin, it is not difficult to allow the display part to change between the vertical and horizontal positions in either turning direction, i.e., both clockwise and counterclockwise. However, in order to prevent the display part from coming into contact with the hinge, it is necessary to largely round the corners of the display part. This invites a problem of reduction of the screen size.
In the technique disclosed in Published Japanese Patent Application No. 2003-319043, since the display part is also supported to the first housing by a single pivot pin, it is not difficult to allow the display part to change between the vertical and horizontal positions both clockwise and counterclockwise. Furthermore, since the display part is once slid upward in changing between the vertical and horizontal positions, it is not necessary to largely round the corners of the display part in order to avoid contact with the hinge. However, this technique involves, after the turning of the display part, an additional step of sliding the display part again to return it to the original level, resulting in a complicated user's operation.
Since the folding portable electronic device disclosed in Published Japanese Patent Application No. 2006-211576 uses the cam mechanism, the display part does not come into contact with the hinge even when it is increased in size. However, in order to allow the display part to turn both clockwise and counterclockwise, the guide groove for guiding the position change of the display part must be increased in size. This also increases the size of the entire folding portable electronic device, thereby deteriorating the portability.